Cardiac cycle flashcards

What is the cardiac cycle?

The sequence of events in one heartbeat, including contraction and relaxation of the heart.

Systole vs. Diastole

Systole is the contraction phase, while diastole is the relaxation phase of the heart.

True or false: The heart has four chambers.

True, because the heart consists of two atria and two ventricles.

What occurs during ventricular systole?

The ventricles contract, pumping blood into the aorta and pulmonary artery.

Fill in the blank: Atrial contraction occurs during _____ phase.

diastole.

What is stroke volume?

The amount of blood ejected by the left ventricle during one contraction.

True or false: Heart rate is constant regardless of activity.

False, because heart rate increases with exercise and decreases during rest.

Compare preload and afterload

Preload is the initial stretching of the cardiac muscle, while afterload is the resistance the heart must overcome to eject blood.

What is the role of the sinoatrial (SA) node?

It acts as the heart's natural pacemaker, initiating electrical impulses for heartbeats.

What happens during diastole?

The heart muscles relax, allowing chambers to fill with blood from veins.

Define cardiac output.

The amount of blood the heart pumps in one minute, calculated as heart rate times stroke volume.

What is isovolumetric contraction?

A phase during systole where the ventricles contract with no volume change, as valves are closed.

Which chamber receives oxygen-rich blood?

The left atrium receives oxygen-rich blood from the lungs.

What is the function of the atrioventricular (AV) node?

It delays the electrical impulse between the atria and ventricles, ensuring proper timing.

True or false: Blood pressure is highest during diastole.

False, because blood pressure peaks during systole.

Difference between heart rate and stroke volume

Heart rate is the number of beats per minute, while stroke volume is the volume of blood per beat.

What is the pressure gradient?

The difference in pressure that drives blood flow from areas of high to low pressure.

Fill in the blank: Cardiac cycle duration at rest is approximately _____ seconds.

0.8 seconds.

What does the term ‘ejection fraction’ mean?

The percentage of blood ejected from the heart during systole compared to total volume.

True or false: The heart is a double pump.

True, because it pumps oxygenated and deoxygenated blood simultaneously.

What is a heart murmur?

An unusual sound during a heartbeat, often caused by turbulent blood flow.

What happens during rapid filling phase?

Blood rushes into the ventricles from the atria due to pressure differences.

Define cardiac reserve.

The difference between maximum and resting cardiac output, indicating heart performance capacity.

What does the term ‘valvular stenosis’ refer to?

Narrowing of heart valves, which restricts blood flow and increases workload on the heart.